The reigning French champions predictably took the lead on the 21st minute when defender Aleksandar Vukotic turned into his own net after Kylian Mbappe whipped in a threatening cross.
Neymar produced another standout performance as he converted a penalty before setting up Mauro Icardi brilliantly from the spot. They pulled off a pass penalty move the likes of Sergio Ramos and Karim Benzema failed to build on.
Kylian Mbappe then added a fourth for PSG to put the game well out of sight with a man advantage.
Maxim Choupo-Moting then grabbed a brace after coming on to make it 6-0 after 90 minutes, with an extra 30 minutes still left to play.
One more goal was added in the last 30 minutes to make it an emphatic 7-0 after 120 minutes.
Neymar reveals that the prolonged lack of action combined with the aggressive nature of Waasland-Beveren left PSG worrying about their fitness.
"Yes we were a little scared," he told beIN SPORTS [via Daily Mail]. "We are here for a friendly match so those types of things should not have been happening.
"We are here to prepare ourselves, but also to be careful. But us too, we gave them a little bit back, so there are no problems.
"We are preparing little by little to get to the maximum then we will be in the finals [Champions League]. The rest is not very important."
PSG boss Thomas Tuchel is looking to get his men in proper fitness ahead of their Champions League campaign next month. So far, his side has shown no rustiness in attack and look to be in good shape ahead of their cup final at the end of the month.
